1. Field
Embodiments described herein generally relate to systems and methods for hydrocarbon processing. More particularly, such embodiments relate to systems and methods for stripping entrained gas from a catalyst in FCC processes.
2. Description of the Related Art
Fluidized Catalytic Cracking (“FCC”) is used to produce transportation fuels such as diesel, gasoline, and other liquid and/or gaseous hydrocarbon products from higher molecular weight feedstocks. The FCC process uses a reactor called a riser where fluidized catalyst particles thermally degrade or crack a higher molecular weight hydrocarbon to form more valuable, lower molecular weight hydrocarbon products. A by-product of the FCC process is a carbonaceous material known as “coke.” Coke has a tendency to deposit on the catalyst particles, deactivating the catalyst. The lower molecular weight hydrocarbon products and the deactivated or spent catalyst particles are recovered from the reactor, and separated to provide a cracked hydrocarbon product and the spent catalyst.
The spent catalyst leaving the FCC riser can contain residual cracked hydrocarbons entrained thereon and/or therein. The spent catalyst is typically stripped in the presence of steam in a catalyst stripper to separate the residual cracked hydrocarbons. In the stripper, falling catalyst is distributed over a network of solid structures or baffles. The network of baffles can promote mixing of the falling catalyst with the upward flowing steam. The network of baffles used in conventional strippers contains rows of individual baffles that are arranged such that the surfaces of each baffle are co-aligned and/or co-planar with each other. During operation, rising gas bubbles have a tendency to coalesce along the underside of these baffles, which reduces stripping efficiency.
There is a need, therefore, for improved systems and methods for stripping catalyst of entrained gas in fluidized catalytic cracking processes.